The present invention relates to a printer particularly a matrix printer with switch-over structure as far as color printing is concerned under utilization of a multiband multicolor ink ribbon. Printers of the type to which the invention pertains use a common ink ribbon having several parallel oriented dye zones or bands of different color and being mounted in stationary ribbon casing from which the ribbon emerges on one end, passes a platen in longitudinal direction along which the print head runs, there being suitable cooperation between the print location defined by the position of the matrix head and the ribbon. The ribbon reenters the ribbon casing at another suitable location such as another casing and establishes in some fashion, possibly including the inside of the casing, a closed loop kind of ribbon path configuration.
The switch over structure for a change in the effective color band of a multicolor band ribbon permits sequential printing in blue, black, green, red and yellow except that cyan is often used in lieu of straight forward blue, and magenta in lieu of regular red. These primary colors can then be used in such a printer for obtaining a multicolor printout by composing images of any kind from at least optically-visually overlapping or merging different color dots.
Basically one distinguishes between two kinds of ribbon cases for cooperation with a matrix type printhead or the like. Smaller ribbon cases or cassettes are mounted onto the particular carriage for the printhead being a type wheel or a multistylus matrix print head. This type of construction limits of course the amount of ribbon that can be made available in a such a cassette so that the available dye and ink supply in a simple cassette is quite limited. Also, there is inherently a fairly small pivot radius as far as changing the orientation of the cassette vis-a-vis the respective print element is concerned. This is added disadvantage because the oppositely oriented curvature of the print platen adds to the limitation of available print area. Larger ink ribbon cassettes may be mounted directly in the printer casing or frame and they transport the ribbon in loop from an exit of this ribbon casing or cassette and back into it as was mentioned above. The invention pertains to this latter kind of multicolor printing and cassette assembly. It should be noted that these larger ribbon casings are able to contain more than 10 even up to 20 -fold the amount of ribbon material that can be accommodated in the earlier mentioned small ribbon cassettes which are mounted on the print casing and carriage itself. An example of a small kind of ribbon cassettes with associated switch over structure for multizone or band ribbons are shown in German printed Patent No. 30 14 820.